Application of modern cardiopulmonary resuscitation (CPR) techniques has resulted in an increasing number of successful resuscitations of cardiac arrest victims. However, only half of those successfully resuscitated regain consciousness, while 20% survive with severe neurologic disability. Research in the biochemistry and pathophysiology of complete global brain ischemia suggests that treatment specifically aimed at certain post-resuscitation abnormalities may reduce the neurologic damage associated with cardiac arrest. Calcium entry blocking drugs are thought to have the potential to improve cerebral blood flow and perhaps block pathologic cerebral metabolic reactions found in post-cardiac arrest brains. This project will evaluate the cardiovascular and neurologic impact of both calcium entry and two calcium blockers, nimodipine and lidoflazine, all given after successful resuscitation of cats following 14 min of cardiac arrest due to induced ventricular fibrillation. The resuscitated animals will be cared for in an environment simulating a hospital intensive care unit for 5 days. Daily neurologic examinations and post-mortem examination of the brain will be used to measure treatment effectiveness. The short-term goal of this study is to provide a basis for supporting, rejecting or modifying an extensive clinical trial of nimodipine administration for brain protection following cardiac arrest. Our long term goal is reduction of neurologic morbidity and mortality in patients successfully resuscitated following cardiac arrest.